Claim 1 of the claims of this specification.
In one embodiment of the present invention, the worm-gear is integrally and concen- trically connected to the shaft of the winding spindle and to a winding knob by which the winding spindle may be rotated. The worm, which engages the worm-gear, is mounted for longitudinal displacement against a bias spring force. This permits one to manually rotate the winding spindle which causes the worm-gear to become operatively disengaged from the normal engagement with the worm wherein the worm and worm-gear function similar to a ratchet and pawl assembly when the winding spindle shaft is manually rotated by turning the winding knob.
In another embodiment of the present invention, the shaft of the winding spindle is releasably connected to the worm-gear by means of a key and key-way construction and may be longitudinally displaced upon releasing the keyed connection with the worm-gear to permit direct rotation of the winding spin- dle independent of the engagement between the worm and worm-gear.
In yet another embodiment, independent rotation of the shaft carrying the winding spindle is accomplished by means of a ratchet and pawl construction provided on the wormgear and a knob-like portion of the shaft carrying the winding spindle. Then the knob may be manually rotated in one direction to effectively wind a replacement string to a pre65 the winding spindle. In many instances, three 130 tuned degree of tension. Once this tension is 2 established, the fine tuning of the string may be accomplished by manipulation of the shaft carrying the worm to cause rotation of the worm-gear in either direction.
Examples of the invention will now be de- 70 scribed with reference to the accompanying drawings in which:
Figure I is-a front elevational view in sec tion of a tuning device constructed in accor dance with the present invention, the section being taken along the centerline of each por tion of the housing; Figure 2 is a right side elevational view in section of the device shown in Fig. 1 illustrat ing the slideable displacement of the shaft carrying the worm, the section being taken along line 2 2 in Fig. 1 and illustrating a modification for providing an outer bearing surface for the winding spindle; Figure 3 is a bottom plan view partially in section of the device shown in Fig. 1 illustrat ing an integrally provided outer bearing means for the winding spindle; Figure 4 is a partial front elevational view of a portion of the device shown in Fig. 1 shown 90 in exploded relationship illustrating a braking means which may be used in connection with the present invention; Figure 5 is a view of that portion of the apparatus shown in Fig. 4 with the compo- 95 nent parts assembled and disposed at a 90 degree angle relative to Fig. 4; Figure 6 is a view similar to the view shown in Fig. 5 illustrating a modified braking means; Figure 7 is a front elevational view in sec tion of another embodiment of a tuning de vice constructed in accordance with the pre sent invention; Figure 8 is a side elevational view partially in section of the embodiment shown in Fig. 7 and which illustrated the displacement of the winding spindle shaft from the worm-gear; Figure 9 is a partial plan view of the device of Fig. 7 illustrating the key-ways provided on a flanged extension of the worm-gear; Figure 10 is a partial plan view of the device of Fig. 7 illustrating a plurality of keys provided on the knob portion of the winding spindle shaft which mate with the key-ways shown in Fig. 9; Figures 11 and 12 are front elevational views of alternative shapes for keying the engagement between the worm-gear and the knob portion of the winding spindle; Figure 13 is a front elevational view in section of another embodiment of a tuning device constructed in accordance with the present invention; Figure 14 is a side elevational view in 125 section of the embodiment shown in Fig. 13, the section being taken along line 14-14 in Fig. 13; Figure 15 is a bottom plan view of the embodiment of Fig. 13 in section, the section 130 GB 2 144 571A 2 being taken along line 15-15 in Fig. 13; Figure 16 is a partial view of a portion of the worm-gear and the knob- portion of the winding spindle as shown in Fig. 15 illustrating the ratchet and paw] construction; Figure 17 is a side elevational view in section of the ratchet and paw] construction shown in Fig. 16; and Figure 18 is a top plan view of portion of the ratchet and paw[ construction shown in Fig. 17.
An improved tuning device for musical string instruments embodying the present invention is shown in Figs. 1 3. Such devices are typically attached to the head portion of the instrument, one for each string. After fixing one end of the string in a conventional manner at a point on the base of the instrument, the string is aligned along the fretted neck portion and is attached to the winding spindle of a given tuning device. The attach ment to the winding spindle is usually accom plished by a criss-cross binding of the string as it is wound about the winding spindle three of four times. This process also establishes a pre-tuned degree of tension in the string which must then be finely adjusted by the user in order to produce the appropriate musi cal sound upon vibration of the string.
Since the device may be attached to the heads of such instruments in any conventional manner, the illustrations and descriptions herein do not deal in detail with the instru ment as a whole.
Referring to Figs. 1 and 2, the improved tuning device includes a housing, indicated generally at 20, which may include a plate 22 secured to the head portion of the instrument 24 by screws 26.
In a conventional manner, the housing in cludes one cylindrical portion 27 to provide a bearing for a shaft 28 provided with a worm 30. The outer extension of shaft 28 is pro vided with a handle or key 32 fixed to the shaft by a screw 34.
Housing means 20 also includes integrally formed cylindrical portion 36 which provides a bearing member for the shaft 38 which is fixed to or otherwise integrally fromed with worm-gear 40. The outer extension of shaft 38 may be provided with a knob or handle 42 fixed to or integrally formed with shaft 38. Alternatively, the end of shaft 38 may be provided with a screw-driver or coin slot, not shown, to facilitate manual rotation.
As shown in Figs. 1 and 2, the worm-gear 40 rotates integrally with shaft 38 and knob 42, and is engaged with and positioned in counter-clockwise rotation by the worm 30. The tension of a tuned string, such as 44, tends to force the worm-shaft 28 toward a brake stop assembly, indicated generally at 46, which is fixed into housing 20 by means of a press fit or in any other suitable conventional manner. The detail of the construction 3 of brake-stop assembly 46 is shown in Figs. 4, 5 and 6 and will be described in detail later herein.
When, knob 42 is manually rotated in a clockwise direction, as shown in Fig. 1, the worm 30 and its associated shaft 28 is caused to move axially out of operative engagement with worm-gear 40. However, a spring 48 is disposed in surrounding relation- ship to shaft 28 between an annular shoulder 49 provided in housing 20 and a washer 51 which is disposed against the lower end of the worm to bias the worm 30 and shaft 28 into operative alignment with worm-gear 40.
Therefore, when knob 42 is rotated in a direction to wind on a loose or relaxed string, the worm 30 and shaft 28 function as a pawl with wormgear 40 acting as a ratchet. This permits a user to manually rotate the winding spindle fixed to shaft 38 directly on a one to one basis independent of the ratio between the operative engagement between the worm 30 and worm- gear 40. Fig. 2 illustrates the axial movement of shaft 28 and worm 30 downwardly compressing spring 48 to a degree wherein the worm 30 and worm- gear 40 function as a pawl and ratchet as described above. Also, the user can manually pull key 34 and hence shaft 28 and worm 30 down- ward, further compressing spring 48, which allows free rotation of knob 42, worm-gear 40, shaft 38, and winding spindle 50 so that a remnant of a broken string may be conveniently removed by simply pulling on the loose end of the string 44.
As shown in Fig. 2, winding spindle 50 comprises a hollow cylinder which is fitted over shaft 38 and may be axially and rotation ally fixed to shaft 38 by a pin 52. A common construction for providing bearing support for winding spindle 50 is shown in Fig. 2 while an alternative open-ended arrangement is shown in Fig. 3. Either form can be effectively used without departing from the spirit of the present invention.
In Figs. 2, spindle 50 fixed to shaft 38 is supported on an outer end by a bearing 54 fixed within a suitable aligned bore provided in the instrument head 24.
Specifically referring to Fig. 3, the open ended winding spindle 50a, is partially hollow and mounted in surrounding relationship to shaft 38 and is fixed thereto by a pin 52. In this construction, the outer end of winding spindle 50a is provided with a narrowed neck 120 portion 58, usually provided with a hole in which the loose end of a string may be inserted. The string is then wound around the neck portion 58.
The tuning device may be secured to the 125 instrument head as shown in Fig. 3 by means of a threaded bearing nut 60 which is threaded to threads conventionally provided in a cylindrical extension 62 of housing 20. A protective washer 64 is typically provided 130 GB2144571A 3 between the head of nut 60 and the instrument head 24. Bearing nut 60 then provides a suitable outer bearing for winding spindle 50a and no other out-board bearing means is required.
Now specifically referring to Figs. 4-6, a brake-stop assembly 46 is illustrated which can be employed in conjunction with the present invention to minimize or prevent de- tuning of the strings under the influence of audio frequency vibrations.
Assembly 46 comprises a cap 66 which is press fit or otherwise fixed into a recess provided in housing 20 and is forced against a washer 68 to create a cavity in which a spring disc 70 and a keyed brake disc 72 are disposed.
The end of worm 30 is provided with a keyway 74. When key-way 74 is engaged by the key of brake disc 72, undesired rotation of worm-shaft 28 is retarded.
An alternative braking means is illustrated in Fig. 6 wherein a cap 76 is provided with a braking cone 78 which is adapted to be frictionally received in a conical recess 80 provided in the end of worm 30.
When the worm is forced onto the braking cone with increasing force, the rotary action of the worm will be frictionally retarded. This tends to retard the detuning of the strings for the reasons discussed above.
Now referring to Figs. 7-12, another embodiment of a tuning device constructed in accordance with the present invention is illus- trated. Those components of this embodiment which are essentially identical will be described using the same reference numerals as used to described the embodiment shown in Figs. 1 -3. Those components or parts thereof which are similar but modified will be identified by the same reference numeral as previously used followed by the letter "b" where it is appropriate.
Specifically referring to Figs. 7 and 8, the embodiment includes a conventionally shaped winding spindle 50a which includes a hollow portion mounted over a portion of shaft 38b and is axially and rotationally fixed to shaft 38b by a pin 52. Winding shaft 38b passes through hollow screw or support bearing 60 which is threaded into a threaded cylindrical extension 62 of the housing, indicated generally at 20. This arrangement includes a protective washer 64 and serves to clamp the entire tuning device unit in a cylindrical bore conventionally provided in the instrument head 24.
Shaft 38b also passes through an axial bore in worm-gear 40b and is free to move axially a distance determined by the position of the winding spindle 50a as it is caused to stop, in one direction, as it contacts a shoulder 79 of retaining sleeve 80 which is co-axially integral with the bore in worm-gear 40b. In the opposing direction, axial movement of shaft 38b 4 GB2144571A 4 is limited by the engagement between knob 42b and a keyed rim on a hub extension 82 provided on worm-gear 40b.
Turning knob 42b is integrally formed or otherwise fixed to winding shaft 38b.
Housing 20, in a similar manner as previ ousiy described in connection with the em bodiment of Figs. 1-3, includes a cylindrical cavity in housing extension 27 that surrounds and provides a bearing for a worm 30 and its integral shaft 28 and also positions the worm and shaft in operative engagement with worm-gear 40b. Turning the worm 30 and shaft 28 by manual manipulation causes the worm-gear 40b to rotate, and when worm gear 40b is connected with the shaft 38b, causes the fixed assembly of shaft 38b, knob 42b and winding spindle 50a to rotate in one direction or the other to fine tune the instru ment. A handle or key 32 is conventionally fixed to the outer end of shaft 28 by a threaded fastener 34 to facilitate the fine tuning process accomplished by rotation of worm shaft 38. The ratio of rotation between the worm shaft 38 and the winding spindle 50a is determined by the worm and worm gear ratio which typically is chosen to be in the range of about fifteen to one.
With continued reference to Figs. 7 and 8, winding shaft 38b is releasably connected to 95 worm-gear 40b by means of a plurality of keys 84, provided on the inner surface of knob 42b, which are adapted to mate with a plurality of keyways 86 provided on face of hub 82, as best seen in Figs. 9 and 10.
When the knob 42b and associated shaft 38b and winding spindle 50a are pulled downwardly as illustrated in Fig. 8, the engagement between keys 86 and 84 is re- leased to permit manual rotation of this assembly free of any relationship with wormgear 40b. In this withdrawn position, one may directly cause rotation of winding spindle 50a in a one to one ratio to wind string 44 around spindle 50a the necessary number of turns to achieve attachment and a state of pre-tuned tension.
At this point, knob 42b is manually forced toward its original position to manipulate the engagement between the keys 84 and keyways 86. The tension of the string in its pretuned state applies a stress force upon the winding spindle 50a which tends to rotate the knob 42b in a direction which tends to secure the engagement between keys 84 and keyways 86.
Upon achieving the pre-tuned degree of tension as described, and reestablishing the keyed connection between knob 42b and hub 82 integrally fixed to worm-gear 40b, the user may now manually turn tuning key 32 to fine tune the string 44 in the conventional manner utilizing the high turn ratio determined by the operative engagement of the worm 30 and worm-gear 40b.
As seen in Fig. 8, a washer 88 surrounds shaft 28 and engages the right end of worm 30. A spring washer 90, which is stressed in assembly is disposed between washer 88 and a bearing washer 91 which abuts a shoulder 92 provided in housing 20. Spring washer 90 is stressed in assembly and the shaft 28 is axially fixed in the operating position with the worm-gear upon tightening threaded fastener 34.
This arrangement functions to retard the free turning of the worm and thus minimize or prevent inadvertent de-tuning of the tuned string which induced by audio vibrations pro- duced during use of the instrument.
Fig. 12 illustrates one alternative shaping of the keyed relationship between hub 82 and knob 42b. The key 84b is adapted to mate with keys 86b to prevent displacement of the keys by force applied to the winding spindle 50a. However, it should be understood that other means may be usefully employed to obtain a releasable keyed relationship between the worm-gear 40b and the winding shaft 38b without departing from the spirit of the present invention.
Another embodiment of a tuning device constructed in accordance with the present invention is illustrated in Figs. 13-18. Similar reference numerals will be used to describe identical or substantially identical components as previously used with reference to the embodiments shown in Fig 1 - 12. Those relevant components which are modified in this embodiment will be identified by a small case letter -c- after the reference numeral.
Referring now to Figs. 13, 14 and 15, a housing, indicated generally at 20, provides an enclosure and bearing for a winding spin- dle 50a which is axially and rotationally fixed to a winding shaft 38c in an identical manner as previously described via pin 52. A hollow bearing nut 60 is also identically mounted to a housing extension 62 to provide a bearing for winding spindle 50a and to bind the whole unit to the instrument head 24. A protective washer 64 is provided between the head of nut 60 and body 24.
The main body portion 36 of housing 20 provides an axial bearing for winding shaft 38c, a cavity surrounding worm-gear 40c and also includes a cylindrical cavity 27 which provides bearing and support for a worm 30 and integrally formed shaft 28 at the appro- priate location to operatively engage worm 30 with worm-gear 40c.
Worm-gear 40c is supported rotationally free and concentric with shaft 38c and is provided with an integrally formed extension or hub 82c which is disposed into an annular cavity in a knob turning handle portion 42c. Knob 42c is generally annular in shape and is provided with knurling or the like on its outer surface to facilitate manual rotation thereof and is integral or otherwise fixed to shaft 38c, GB2144571A 5 which in turn,. is fixed to winding spindle 50a as previously described.
Hub 82c of worm-gear 40c is provided with a plurality 6f radially disposed slots 93 which are adapted to receive a pawl 94 disposed to freely slide toward the inner surface of knob 42c. A spring 95 is disposed in a counterbore 97 aligned with each slot 93 to bias the pawls 17 outwardly toward a plurality of ratchet serrations 96 provided on the inner surface of knob 42c.
When the pawls 94 are engaged with the ratchet serrations 96 under the bias force of springs 95, the knob 42c may be manually turned clockwise as shown in Fig. 15. The hub 82c and worm-gear 40c remain stationary as the pawls are forced to retract during the clockwise rotation of knob 42c. In this manner, it should be readily apparent that knob 42c, shaft 38c and spindle 50a may be rotated in a clockwise direction to wind a string around the neck portion of spindle 50a independently of the operative turning ratio between worm-gear 40c and worm 30. Once the string has been wound upon spindle 50a sufficiently to obtain a degree of pre-tuned tension, rotation of shaft 28 and worm 30 may be used to fine tune the string tension to produce the desired musical tone. Once the string 44 is under tension, rotation of key 32 and the associated shaft 28 and worm 30 in one direction or the other will operate to increase or decrease the string tension accordingly in a turning ratio established by the worm and worm-gear.
To provide for means to reduce or prevent undesirable turning of the worm and hence the worm-gear induced by audio vibrations during use of the musical instrument, an identical arrangement as described in the embodiment shown in Figs. 7 and 8 may be employed.
The washers 88 and 91 and the spring washer 90 when stressed in assembly, tend to retard the free turning of worm 30. The key 110 32 is fixed to an upper portion of shaft 28 by threaded fastener 32 to complete the as sembly.
From the foregoing description it should be readily appreciated that the present invention provides a very significant improvement in string instrument tuning devices. A user may quickly and easily replace worn or broken string with a very dramatic decrease in time and effort, yet fine tune each string in the conventional manner. Further, the construction of the device incorporating the advantages of the present invention does not interfere with the typical and accustomed manner of fine tuning the strings.
CLAIMS 1. In a tuning device for musical string instruments, the combination of a housing means; a first shaft means rotatably mounted 130 in a said housing and provided with a worm, one end of said first shaft means extending out of said housing and carrying a fixed handle-like key to facilitate manual rotation of said first shaft means, second shaft means mounted in said housing at approximately a right angle to said first shaft means and including one end extending out of said housing and provided with means to receive the end of a string to be mounted thereon; a worm-gear rotatably mounted within said housing in surrounding co-axial relationship to said second shaft means and surrounding coaxial relationship to said second shaft means and normally in engaged alignment with said worm on said first shaft means; means provided on the opposing end of said second shaft means relative to the end to which the string is attached to facilitate direct manual rotation of said second shaft means in at least one direction; and means associated with one of said shaft means to permit operative disengagement of said worm-gear from either said worm or from said second shaft means to effect the direct rotation of said second shaft means in at least said one direction independent from the operative turning ratio established between said worm and worm-gear.